Rusty wrote:>> Yes, NR_CPUS needs to get to userspace somehow sanely if we want to fix>> this in general.

On Sun, Jun 06, 2004 at 05:16:57AM -0700, Paul Jackson wrote:> Are you saying that NR_CPUS is needed, or just the number of longs in a> cpumask (sizeof (cpumask_t), essentially)?> I can see where the size is needed, in order to make the system calls to> set and get masks of arbitrary size. Since these sizes are a multiple> of sizeof(long), at a minimum this means user code needs to know the> number of longs in a mask. Though the number of bytes, as in> sizeof(cpumask_t), rather than of longs, is perhaps a less surprising> interface.> I can't see where the user code cares whether NR_CPUS is 47 or 48?> Am I missing something?> I am a firm believer in passing the minimum essential information across> major boundaries. Passing too much creates maintaince problems, and> encourages misuse of information, resulting in bogus user code.

You've been told, and several times already. The current example isuserspace needing to know when to stop trying to online cpus.